Automatic fluid-pressure brake apparatus



(No Model.) I

W. T. BOTHWELL.

AUTOMATIC FLUID PRESSURE BRAKE APPARATUS.

No. 595,760. I Patented Dec. 21, 1897.

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AUTOMATIC FLUID-PRESSURE BRAKE APPARATUS.

SPECIFICATION forming part of Letters Patent No. 595,760, dated December21, 1897. Application filed November 4, 1897. Serial No. 657,435. (Nomodel.)

To aZZ whom it may concern Be it known that I,W1LLIAM T. BOTHWELL, acitizen of the United States, residing at J ersey City, in the county ofHudson and State of New Jersey, have invented certain new and usefulImprovements in Automatic Fluid- Pressure Brake Apparatus; and I dodeclare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled. in the art to which'itappertains to make and use the same.

My invention relates to improvements in automatic fluid-pressure brakeapparatus; and it has for its general object to provide such anapparatus in which the brakes may be applied with great force in makingemergency stops without involving the maintenance of a high pressure inthe auxiliary reservoir and train-pipe, and one in which the degree offorce with which the brakes are applied may be quickly or graduallyreduced as the speed of the train slackens in order to prevent thesliding of the wheels and the objectionable results incidentthereto,-and in which the reduction of force is effected with the lossof but a minimum amount of pressure and at the same time the auxiliaryreser voir is replenished,so as to admit of the brakes being reappliedwith full force at any time before the train comes to a full stop.

Other objects and advantages of the invention Will appear from thefollowing description and claims when taken in connection with theannexed drawing, in which The figure is a vertical section illustratingthe two brake-cylinders and two triple valves of my improved apparatusin conjunction with the auxiliary reservoir, which is shown inelevation.

Referring by letter to said drawing, A B indicate the twobrake-cylinders of my apparatus, which are preferably placed side byside, as shown, and O and D indicate the pistons, which are arranged inthe cylinders A B, respectively, and may have their rods a b surroundedby the usual springs d for releasing the brakes when the pressure isremoved. The said rods Ct b of the pistons G D are designed to beconnected together and with the brake-beams in such a manner that whenone or both of the pistons are forced forwardly by the pressure behindthem the brake-beams F indicates the auxiliary reservoir of my apparatusI indicates the train-pipe, and G H indicate the triple valves, whichare connected with the reservoir by the pipes Z, m, and 'n and with thetrain-pipe I by the pipes 19 and q. The triple valve G is generallysimilar to that disclosed in my prior application, filed November 23,1893, Serial No. 491,725, and it has a port or passage 7', which leadsfrom the interior of its valve-chamber .9 into the interior of thebrake-cylinder A, as shown. The outer head i of said triple valve G isprovided with a port or passage to for connection/with the train-pipebranch q, and this port or passage uleads into the valvechamber 3 on oneside of the piston and contains an annulus 12, which annulus furnishes abearing for one end of the cushion or resistance spring 21;, theopposite end of which may bear against the inner end of the trainpipebranch. Said head i is also provided with a port or passage as, whichcommunicates at its inner end with the valve-chamber s and has its outerend closed by a nut, cap, or the like, and in this passage 00 is avalveseat y, and passing laterally from said passage above thevalve-seat y is a passage z in the body of the valve-casing, for apurpose presently described.

Arranged within the passage m above the valve-seat y is a check-valve awhich is designed to bear upon said seat when pressure in the train-pipehas been reduced, as will be presently explained, and to raise from saidseat and allow communication to be established between the passages 00 2when pressure has been increased in the train-pipe.

Within the valve-chamber s is arranged a bushing 12, which is turned toform a stop or shoulder 0', designed to limit the movement of the valvepiston. This bushing 19' has formed in it a valve-seat cl, and leadingfrom this valve-seat is an exhaust-passage e,which is arranged about theproportional distance illustrated from the brake-cylinder passage 0,which also leads from the valve-seat. In the triple-valve casing at asuitable distance from the forward end is an annular groove f, whichcommunicates with a passage w, and this annular groove is covered, asshown, by the bushing 12, which has a circularseries of holes gconnecting the valve chamber with said annular groove. The triple-valvecasing is also provided with a large passage h, which communicates atone end with the valve-chamber s on one side of the piston andcommunicates at its opposite end with said valve chamber 011 theopposite side of the piston through the medium of the passages m 2, and,furthermore, communicates with the auXiliary-reservoir port or passage1', as shown. At the base of the port or passage 'i is a valve-seat, andon this valve-seat is arranged a check-valve j,which preferably has thecommunicating vertical and transverse passages k' Z, so thatfluid-pressure can at the same time move through both passages for apurpose which will presently appear.

M indicates a piston which is arranged in the larger portion of thevalve-chamber s and is provided on its forward side witha projectionm',which is designed to bear against the spring-backed annulus t, and Nindicates a slide-valve which is mounted on the rod 01 of the piston M.This valve N is arranged to slide on the seat (Z, and it is provided inits under side with a recess 19 and is also provided with avertically-disposed aperture q, the purpose of which will presently bedescribed.

The valve-piston M when in its extreme forward position rests againstthe forward head 6 of the valve-casing, as shown, and I thereforeprovide the groove or passage 7' in the inner side of said head i inorder to connect the train-pipe port or opening and the passage as whenthe valve-piston is in such position.

The triple valve H, which has its valvechamber 8 connected with thebrake-cylinder B by a passage W, is provided with a train-pipe port oropening it, an auxiliary- IGSGIVOll pOltv 01 opening 71 {L11XhLLlSt-pZLS- sage 6 an annular groove f communicating with the port orpassage F, a bushing Z7 having a shoulder 0 and openings 9 communieatingwith the grooy e f avalve kiarranged in the, port or passage 2*, apassage 7%, connecting the valve-chamber and the port or passage 7?, apiston l\I, and a valve N, and is generally similar to the triple valveG in all respects except that itlacks the passages 9", cc, and z and thecheclcvalve a, before described.

20 indicates aspring which backs the annulus 4), against which the stemof the piston BI of the triple valve 0 bears, and 10 indicates thespring which backs the annulus 0, against which the stem of the piston31 of the triple valve 11 bears, and which spring 10 is stronger thanthe spring to, for a purpose presently described.

In the drawing the slide valves N N of the triple valves G H,respectively, are shown in the positions which they are caused to assumeby a sudden and material reduction of the pressure in the train-pipe.When the valves N N are in this position, the brakecylinder passages rv" are entirely uncovered and the fluid pressure from the auxiliaryreservoir will therefore pass through the port or passage 1 passage h,valve-chamber s, and passage 9' of the triple valve G into thebrake-cylinder A, and through the port or opening 2' passage 7L2,Valvechamber s, and passage r of the triple valve ll into thebrake-cylinder B, and acting against the pistons O D in both cylinders AB will, by reason of the two cylinders and pistons being employed, applythe brakes with great power and force, although the degree of power ofthe pressure in the auxiliary reservoir may be low as compared with thatof the pressure normally maintained in the auxiliary reservoirs ofautomatic fluid-pressure brakes at present in use. The powerful andforcible application of the brakes above described greatly exceeds theforce which is necessary or even safe at ordinary speeds, or which couldbe safely applied at any speed if it was continued without reduction asthe' speed of the train diminished. It is necessary for this reason thatthe initial force of the application should. be gradually reduced as thespeed of the train diminishes in order to prevent the Wheels from being.locked so tightly that they will slide on the rails. This may beeffected by the engineer manipulatinghis valve so as to graduallyincrease the pressure in the trainpipe. When this is done, it will beseen that by reason of the spring in of the valve H being stronger thanthe spring to of the valve Gr, while the piston M and valve N of thevalve G will remain in the position shown, the piston M and valve N ofthe valve H will be moved, so that said valve N, through the medium ofthe recess in its under side, will effect communication between thebrakecylinder passage '1' and the exhaust-passage e When this is done,the degree of force with which the brakes are applied will be reduced bythe exhaust of the fluid-pressure froln the cylinder B alone, andconsequently it Will be seen that but a minimum amount of fluid-pressureis lost. The exhaust of the fluid -pressure from the cylinder B may beeffected gradually or quickly, as is most dresirable, by the gradual orquick increase of the pressure in the train-pipe, and itwill beperceived that simultaneously with the exhaust of the pressure from thecylinder B the auxiliary reservoir will be replenished, so as to admitof the brakes being reapplied with full force at any time before thetrain comes to a full stop, which is an important desideratum.

If it is desired to still further reduce the force or power of theapplication after the fluid-pressure has been exhausted from thecylinder B Without entirely releasing the brakes, such reduction may beeifected by the engineer gradually increasing the pressure in thetrain-pipe, so as to overcome the pressure back of the piston M, andmove the valve N, so as to enable the same to partially or entirelycover the passage r; and when it is desired to release the brakes it issimply necessary for the engineer to increase the trainpipe pressuresufficiently to move the piston M and valve N rearwardly the fullextent, when the recess 10 of said valve will effect communicationbetween the passage ,1" and exhaust-passage e and will close both ofsaid passages to the valve-chamber, so that the fluid-pressure enteringfrom the train-pipe will pass to the auxiliary reservoir and replenishthe same.

To make a service application with my improved apparatus, it is simplynecessary for the engineer to reduce the train-pipe pressure sufficientto enable the auxiliary-reservoir pressure by acting on the piston M ofthe triple valve G to move the valve Nthereof and uncover the port orpassage 9", leading to the brake-cylinder A. This movement of the pistonM and valve N in the triple valve G is effected without moving thepiston M and valve N of the triple valve H on account of the strongerspring-back of said piston M of the valve H, and it permits thefluidpressure to enter the brake-cylinder A alone, and consequently thebrakes will not be applied with such great force as when thefluid-pressure is admitted into both brake-cylinders.

When the brakes are applied by the admission of fluid-pressure into thecylinder A alone, they may be released in the usual man ner byincreasing the pressure in the trainpipe sufficient to overcome theauxiliary-reservoir pressure.

WVhen the degree of force with which the brakes are initially applied inthe making of an emergency or a service stop is diminished in the mannerbefore described to prevent locking of the wheels and it is desiredbefore the train comes to a full stop to reapply the brakes with thesame force as the initial application, it is simply necessary for theengineer to reduce the pressure in the train-pipe, so as to enable theauxiliary-reservoir pressure to move the piston M and the valve N of thetriple valve H so as to admit the fluidpressure to the brake-cylinder B.In other words, while the piston M and valve N of the triple valve Grest in the position illustrated or in a position to admitfluid-pressure to the cylinder A through the port q the piston M andvalve N of the triple valve H may be moved by reason of the degree ofpressure in the train-pipe being varied, so as to connect thebrake-cylinderpassage r and the exha ustpassage e to effect the exhaustof fluid-pressure from the brake-cylinder and diminish the degree offorce with which the brakes are applied, and may then be moved so as tobring the port q over the passage 1*, or so as to entirely uncover saidpassage r and readmit fluid-pressure to the cylinder B to effect areapplication of the brakes with the initial force.

By reason of the apparatus described brakes may be applied with ampleforce to make a service stop and may be applied with great power andforce to make an emergency stop, although the degree of power of thepressure in the auxiliary reservoir and trainpipe may be low as comparedwith that of the pressure normally maintained in the auxiliaryreservoirs and train-pipes of automatic fluid-pressure brakes at presentin use, which is a very important advantage, as is obvious.

While my improved apparatus is designed and adapted to powerfully applythe brakes when but a low degree of pressure is maintained in theauxiliary reservoir and trainpipe, yet it may be used to advantage whena high degree of pressure is maintainedin both the auxiliary reservoirand train-pipe, and consequently it will be seen that it may be used inconjunction with automatic airbrake apparatus, such as at present inusethat is to say, it may be connected with the same train-pipe as theordinary apparatus and may be operated in concert with such apparatus byvarying the degree of pressure in the train-pipe. It is desirable,however, when my improved apparatus is used in conjunction with theordinary apparatus, or

when a high degree of pressure is maintained in the reservoir andtrain-pipe, to admit the fluid-pressure into but one of thebrake-cylinders in order to make a service stop, as its admission intoboth cylinders would. result in a too forcible application of thebrakes. To accomplish this without interfering with the operation. ofthe triple valve H when an emergency application is to be made, I makethe spring 10, which backs the annulus 21, against which the stem of thepiston M of the triple valve H bears, stronger than the correspondingspring w of the triple valve G,

- as before described. Consequently it will be seen that a greaterreduction of pressure in the train-pipe is necessary in order to enablethe auxiliary-reservoir pressure to move the piston M and its valve Nthan is necessary to enable the auxiliary-reservoir pressure to move thepiston M and valve N of the triple valve G. By reason of this it will beappreciated that when the degree of pressure in the train-pipe isreduced slightly below that of the pressure in .the auxiliary reservoirthe piston M and valve N of the triple valve G will be moved by theauxiliary reservoir pressure, While the piston M and valve N of thetriple valve H will remain stationary and the fluid-pressure will enterthe cylinder A alone. sure in the train-pipe is reduced to aconsiderable extent below that of the auxiliary-reservoir pressure, suchauxiliary pressure will move the pistons and valves of both triplevalves and entering the cylinders A B will When, however, the degree ofpreseffect a powerful application of the brakes, such as is desirablewhen an emergency stop is to be made.

For the sake of clearness I would have it distinctly understood thatwhile the triple valve G is preferable because fluid-pressure may be fedto the auxiliary reservoir when the brakes are applied and while theyare applied I do not desire to be understood as confining myself to suchconstruction of triple valve, as triple valves of any suitable conlstruction may be employed in lieu of the triple valves G H. i

I have specifically described the construction and arrangement of myimproved apparatus in order to impart a full, clear, and exactunderstanding of the same; but I do not desire to be understood asconfining myself to such construction and arrangement, as such changesor modifications may be made in practice as fairly fall within the scopeof my invention.

Having described my invention, what I claim is 1. In an automaticfluid-pressu re brake system, the combination of an auxiliary reservoir,a train-pipe, two brake-cylinders A, B, a triple valve having aValve-cha1nber, trainpipe, auxiliary-reservoir and exhaust openings orports communicating with the valvechamber and also having an opening orport communicating with the valve-chamber and the brake-cylinder A, avalve in said chamber adapted to control communication between theexhaust and brake-cylinder openings or ports and between thevalve-chamber and brake-cylinder opening or port, a piston to operatesaid valve, a check-valve adapted to control communication between theauxiliary-reservoir port or opening and that part of the valve-chamberin front of the piston, a passage connecting the auxiliary-reservoiropening or port and the valve-chamber on the side of the piston withwhich the brake-cylinder port or opening communicates, a passageconnecting the auxiliary-reservoir port or opening and the valve-chamberon the side of the piston with which the train-pipe port or openingcommunicates, and a check-valve arranged in this latter passage andadapted to permit air to pass through the passage to theauxiliary-reservoir port or opening and prevent its return through thepassage, and

a second triple valve having a valve-chamber, train-pipe,auxiliary-reservoir, and exhaust openings or ports communicating withthe valve-chamber and also having an opening or port communicating withthe valvechamber and the brake-cylinder B, a valve in said chamberadapted to control communication between the exhaust and brake-cylinderopenings or ports and between the valvechamber and brake-cylinderopening or port, a piston to operate said valve, a check-valve adaptedto control communication between the auxiliary-reservoir port or openingand that part of the valve-chamber in front of the piston, and a passageconnecting the auxiliary-reservoir opening or port and the valvechamberon the side of the piston with which the brake-cylinder port or openingcommunicates, substantially as and for the purpose set forth.

2. In an automatic fluid-pressure brake system, the combination of anauxiliary reservoir, a train-pipe, two brake-cylinders A, B, a triplevalve H, having a valve-chamber, train-pipe, auxiliary-reservoir andexhaust openings or ports communicating with the valve-chamber and alsohaving an opening or port communicating with the valve-chamber and thebrake-cylinder B, a valve in said chamber adapted to controlcommunication between the exhaust and brake-cylinder openings or portsand between the valve-chamber and brake-cylinder opening or port, apiston to operate said valve and a spring backing the piston, and asecond triple valve G, having a valve-chamber, train-pipe,auxiliaryreservoir and exhaust openings or ports coinmunicating with thevalve-chamber and also having an opening or port communicating with thevalve-chamber and the brake-cylinder A, a valve in said chamber adaptedto control communication between the exhaust and brake-cylinder openingsor ports and between the valve-chamber and brake-cylinder openings orports, a piston to operate said valve, and a spring backing said piston;said spring being of less strength than the spring backing the piston ofthe triple valve I-I, substantially as specified.

3. In an automatic fluid-pressure brake system, the combination of anauxiliary reservoirF, a train-pipe, two brake-cylinders A, B,

a triple valve I'I, connected with the train-pipe, auxiliary reservoirand brake-cylinder B, and having an exhaust port or opening, and adaptedto eifect communication between the auxiliary reservoir F, and thebrake-cylinder 13, communication between said brake-cylinder and anexhaust and communication between the train-pipe and the auxiliaryreservoir F, and a triple valve G, connected with the trainpipe,auxiliary reservoir F, and brake-cylinder A, and adapted to effectcommunication between the auxiliary reservoir F, and the brake-cylinderA, communication between said brake-cylinder and an exhaust andcommunication between the train-pipe and the auxiliary reservoir F, andembodying such a construction that a greater pressure in the train-pipeis necessary to move its valve than is necessary to move the valve ofthe triple valve II,'substantially as and for the purpose set forth.

4. In an automatic fluid-pressure brake system, the combination of anauxiliary reser voir, a train-pipe, two brake-cylinders and two triplevalves connected with the auxiliary reservoir and the train-pipe andeach connected with one of the brake-cylinders and each having anexhaust and a spring backing its piston; one of said springs beingstronger than the other and the valve which is provided with the weakerspring having a passage for affording an escape for the trainpipepressure, substantially as specified.

5. In an automatic fluid pressure brake mechanism, the combination witha trainpipe, an auxiliary reservoir, and a plurality of brake-cylinders,of valve mechanism operative by a partial reduction of train-pipepressure for automatically supplying fluidpressure to one or more of thebrake-cylinders according to the rapidity of the variations in train-pipe pressure between certain limits above the atmosphere and alsooperative by an increase of train-pipe pressure for exhaustingfluid-pressure from one or more of the brake-cylinders according to thevariations in train-pipe pressure,substantially as specified.

6. In an automatic fluidpressure brake mechanism,in which applicationsof the brake may be effected by varying the pressure in the train-pipebetween certain limits above the pressure of the atmosphere, thecombination with a train-pipe, an auxiliary reservoir, and a pluralityof brake-cylinders; of valve mechanism whereby fluid under pressure isadmitted to one of the brake-cylinders on a moderate or gradualreduction of the trainpipe pressure and to both brake-cylinders on amore rapid reduction of train-pipe pressure, and whereby fluid-pressureis exhausted from one brake-cylinder on a moderate or gradual increaseof train-pipe pressure and from both cylinders on a greater or morerapid increase of train-pipe pressure, substantially as specified.

In testimony whereof I affiX my signature in presence of two witnesses.

WILLIAM T. BOTHWELL. Witnesses:

FREDERICK PLATZ, D. F. PUTNAM.

